Rescue workers on a boat search the Hudson River south of the Tappan Zee Bridge for two people who fell into the water during a boat crash Saturday in Piermont, N.Y. Their boat struck a barge under the bridge, according to the Coast Guard. (ASSOCIATED PRESS / Julio Cortez)

WHITE PLAINS, N.Y. (AP) — The barge that was involved in the Hudson River collision that killed a bride-to-be and her fiance’s best man is just a hint of the heavy construction traffic that will challenge boaters during the building of a new bridge in the New York suburbs, experts said Monday.

At times during the next few years there could be 90 barges in the river as part of work on the $3.9 billion Tappan Zee Bridge project, said Lt. James Luciano, commander of the Westchester County police marine unit.

That would be in addition to the temporary platforms that are being built and the two permanent side-by-side spans.

“It’s going to be a mess for a long time,” said Rockland County Sheriff’s Department Chief William Barbera.

The wedding party’s speedboat hit a barge Friday night, killing Lindsey Stewart of Piermont and Mark Lennon of Pearl River, both 30, and injuring four, including the groom, two weeks before the wedding.

The barge was one of three in the area, all properly moored and lighted, said Coast Guard spokesman Charles Rowe. The barge’s illumination is part of the investigation, Rockland County Sheriff Louis Falco said Sunday.

But investigators believe, based on witness accounts, that the man piloting the speedboat, Jojo John, may have been intoxicated, Falco said.

He is charged with vehicular homicide in the death of Stewart, the bride-to-be, whose body was found Sunday. Her funeral was scheduled for Thursday at the church in Pearl River where she would have been married.

District Attorney Thomas Zugibe said Monday that a grand jury is being assembled and he is seeking upgraded charges, apparently based on Sunday’s recovery of Lennon’s body. He was to be the best man at Stewart’s Aug. 10 wedding to Brian Bond of Piermont.

Stewart died from both drowning and severe head injuries and Lennon also drowned but had only minor bodily injuries, the county medical examiner said Monday.

Bond and John were still hospitalized Monday. The names of the other two survivors have not been made public on the ground they are witnesses.

Falco said authorities on Monday began a reconstruction of the accident. Barbera said that would involve a crime scene unit taking photos and measurements.

The sheriff’s office said it was awaiting the results of an alcohol test on John’s blood. He has a previous arrest on a drug possession charge and another on a conspiracy charge, Barbera said.

A call to John’s lawyer was not immediately returned.

Rowe said wide-ranging measures have been taken to help get boaters safely through the busy construction area. Safety zones have been established, restricting construction vessels to specified areas around the bridge, and boaters have been notified.

The number of construction vessels will ebb and flow, he said, “but the vast majority will be there only during daylight.”

Barges are more likely to be stationary, and Rowe said they have to be lighted “in such a manner that they are visible from one nautical mile away (about 1.15 land miles) no matter the direction of approach.”

The speedboat in Friday night’s accident was crossing the river from west to east, from Piermont to Tarrytown, about 30 miles north of Manhattan.

The safety zones will not be changing even as construction vessels multiply on the river, Rowe said.

“The safety zones are big enough to accommodate all the construction,” he said. “They were established early on and we’ve published them on our website and out to mariners in various ways.”

Rowe said boaters can be confident that the main channel of the river will always be open because “it’s a vital shipping channel, with oil tankers and container ships, and it can’t be obstructed. It’s marked by buoys and it must be kept clear at all times.”

He said boaters should simply approach the construction zone the way they would on a highway, “keeping your speed sensible.”

As for enforcement, he wouldn’t give specifics of Coast Guard deployment, but said, “Were I a mariner, I would be sure I follow the rules of the road in the vicinity of the Tappan Zee Bridge.”